ITGA3

ITGA3 is a human gene that encodes the integrin alpha-3 subunit, a transmembrane protein belonging to the integrin alpha chain family. The protein partners with the beta-1 subunit to form the α3β1 integrin receptor, with α3β1 serving as the principal heterodimer in most contexts. In some cell types, additional beta partners have been reported, but α3β1 is the best characterized form.

Functionally, α3β1 mediates cell adhesion to laminin-containing components of the basement membrane, notably laminin-332 (laminin-5). This adhesion supports epithelial attachment to the basement membrane, helps maintain tissue architecture, and guides cell migration during processes such as wound healing and development. Signaling downstream of α3β1 can influence cytoskeletal organization, cell survival, and gene expression through pathways associated with focal adhesions and related kinases.

ITGA3 is widely expressed in epithelial tissues, including skin, kidney, lung, and mucosal surfaces. Its expression is regulated during development, differentiation, and in response to injury or inflammation. In disease contexts, altered ITGA3 expression or function has been linked to changes in cell adhesion and invasive behavior in certain cancers. Rare germline variants have been associated with congenital disorders that affect epithelial tissues, reflecting the critical role of α3β1–mediated adhesion in basement membrane integrity of kidney and skin.

Genetically, ITGA3 is part of the integrin alpha chain family and encodes a protein of substantial extracellular domain, a single-pass transmembrane region, and a short cytoplasmic tail. The molecule is subject to post-translational modifications that influence its activity and interactions.